Grading of carotid artery stenosis using high resolution dynamic magnetic resonance angiography in comparison to intraarterial digital subtraction angiography. Are stenoses over 70% reliably detectable?

Purposes: Evaluation of high resolution dynamic magnetic resonance angiography (ceMRA) in detection and graduation of carotid artery stenosis in comparison to intraarterial digital subtraction angiography. Materials and Methods: Magnetic resonance angiography and intraarterial digital subtraction angiography was performed in 65 patients with suspected carotid artery stenosis by ultrasound examination. Detection and graduation of carotid artery stenosis by magnetic resonance angiography were compared to those of intraarterial digital subtraction angiography after stenosis grading according to NASCET criteria. Results: All magnetic resonance angiographies were of excellent quality, with 46 stenoses type I and II and 12 stenoses type III NASCET correctly identified and classified by magnetic resonance angiography. Overestimation was found in 4 cases and underestimation in 2 cases. Both modalities detected 13 occlusions. Sensitivity and specificity of ceMRA were 92%. The positive predictive value was 86% and the negative predictive value 96%. Conclusion: High resolution dynamic magnetic resonance angiography is suitable in detecting and classifying carotid artery stenoses over 70% with high sensitivity and specificity in comparison to intraarterial digital subtraction angiography. Intraarterial digital subtraction angiography should only be performed in critical cases.